2 * ALSA input and output
3 * Copyright (c) 2007 Luca Abeni ( lucabe72 email it )
4 * Copyright (c) 2007 Benoit Fouet ( benoit fouet free fr )
6 * This file is part of FFmpeg.
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 * ALSA input and output: common code
26 * @author Luca Abeni ( lucabe72 email it )
27 * @author Benoit Fouet ( benoit fouet free fr )
28 * @author Nicolas George ( nicolas george normalesup org )
31 #include <alsa/asoundlib.h>
32 #include "libavformat/avformat.h"
34 #include "alsa-audio.h"
36 static av_cold snd_pcm_format_t codec_id_to_pcm_format(int codec_id)
39 case CODEC_ID_PCM_S16LE: return SND_PCM_FORMAT_S16_LE;
40 case CODEC_ID_PCM_S16BE: return SND_PCM_FORMAT_S16_BE;
41 case CODEC_ID_PCM_S8: return SND_PCM_FORMAT_S8;
42 default: return SND_PCM_FORMAT_UNKNOWN;
46 static void alsa_reorder_s16_out_51(const void *in_v, void *out_v, int n)
48 const int16_t *in = in_v;
63 static void alsa_reorder_s16_out_71(const void *in_v, void *out_v, int n)
65 const int16_t *in = in_v;
82 #define REORDER_DUMMY ((void *)1)
84 static av_cold ff_reorder_func find_reorder_func(int codec_id,
89 codec_id == CODEC_ID_PCM_S16LE || codec_id == CODEC_ID_PCM_S16BE ?
90 layout == AV_CH_LAYOUT_QUAD ? REORDER_DUMMY :
91 layout == AV_CH_LAYOUT_5POINT1_BACK ?
92 out ? alsa_reorder_s16_out_51 : NULL :
93 layout == AV_CH_LAYOUT_7POINT1 ?
94 out ? alsa_reorder_s16_out_71 : NULL :
99 av_cold int ff_alsa_open(AVFormatContext *ctx, snd_pcm_stream_t mode,
100 unsigned int *sample_rate,
101 int channels, enum CodecID *codec_id)
103 AlsaData *s = ctx->priv_data;
104 const char *audio_device;
106 snd_pcm_format_t format;
108 snd_pcm_hw_params_t *hw_params;
109 snd_pcm_uframes_t buffer_size, period_size;
110 int64_t layout = ctx->streams[0]->codec->channel_layout;
112 if (ctx->filename[0] == 0) audio_device = "default";
113 else audio_device = ctx->filename;
115 if (*codec_id == CODEC_ID_NONE)
116 *codec_id = DEFAULT_CODEC_ID;
117 format = codec_id_to_pcm_format(*codec_id);
118 if (format == SND_PCM_FORMAT_UNKNOWN) {
119 av_log(ctx, AV_LOG_ERROR, "sample format 0x%04x is not supported\n", *codec_id);
120 return AVERROR(ENOSYS);
122 s->frame_size = av_get_bits_per_sample(*codec_id) / 8 * channels;
124 if (ctx->flags & AVFMT_FLAG_NONBLOCK) {
125 flags = SND_PCM_NONBLOCK;
127 res = snd_pcm_open(&h, audio_device, mode, flags);
129 av_log(ctx, AV_LOG_ERROR, "cannot open audio device %s (%s)\n",
130 audio_device, snd_strerror(res));
134 res = snd_pcm_hw_params_malloc(&hw_params);
136 av_log(ctx, AV_LOG_ERROR, "cannot allocate hardware parameter structure (%s)\n",
141 res = snd_pcm_hw_params_any(h, hw_params);
143 av_log(ctx, AV_LOG_ERROR, "cannot initialize hardware parameter structure (%s)\n",
148 res = snd_pcm_hw_params_set_access(h, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
150 av_log(ctx, AV_LOG_ERROR, "cannot set access type (%s)\n",
155 res = snd_pcm_hw_params_set_format(h, hw_params, format);
157 av_log(ctx, AV_LOG_ERROR, "cannot set sample format 0x%04x %d (%s)\n",
158 *codec_id, format, snd_strerror(res));
162 res = snd_pcm_hw_params_set_rate_near(h, hw_params, sample_rate, 0);
164 av_log(ctx, AV_LOG_ERROR, "cannot set sample rate (%s)\n",
169 res = snd_pcm_hw_params_set_channels(h, hw_params, channels);
171 av_log(ctx, AV_LOG_ERROR, "cannot set channel count to %d (%s)\n",
172 channels, snd_strerror(res));
176 snd_pcm_hw_params_get_buffer_size_max(hw_params, &buffer_size);
177 /* TODO: maybe use ctx->max_picture_buffer somehow */
178 res = snd_pcm_hw_params_set_buffer_size_near(h, hw_params, &buffer_size);
180 av_log(ctx, AV_LOG_ERROR, "cannot set ALSA buffer size (%s)\n",
185 snd_pcm_hw_params_get_period_size_min(hw_params, &period_size, NULL);
186 res = snd_pcm_hw_params_set_period_size_near(h, hw_params, &period_size, NULL);
188 av_log(ctx, AV_LOG_ERROR, "cannot set ALSA period size (%s)\n",
192 s->period_size = period_size;
194 res = snd_pcm_hw_params(h, hw_params);
196 av_log(ctx, AV_LOG_ERROR, "cannot set parameters (%s)\n",
201 snd_pcm_hw_params_free(hw_params);
203 if (channels > 2 && layout) {
204 s->reorder_func = find_reorder_func(*codec_id, layout,
205 mode == SND_PCM_STREAM_PLAYBACK);
206 if (s->reorder_func == REORDER_DUMMY) {
207 s->reorder_func = NULL;
208 } else if (s->reorder_func) {
209 s->reorder_buf_size = buffer_size;
210 s->reorder_buf = av_malloc(s->reorder_buf_size * s->frame_size);
215 av_get_channel_layout_string(name, sizeof(name), channels, layout);
216 av_log(ctx, AV_LOG_WARNING,
217 "ALSA channel layout unknown or unimplemented for %s %s.\n",
219 mode == SND_PCM_STREAM_PLAYBACK ? "playback" : "capture");
227 snd_pcm_hw_params_free(hw_params);
233 av_cold int ff_alsa_close(AVFormatContext *s1)
235 AlsaData *s = s1->priv_data;
237 av_freep(s->reorder_buf);
242 int ff_alsa_xrun_recover(AVFormatContext *s1, int err)
244 AlsaData *s = s1->priv_data;
245 snd_pcm_t *handle = s->h;
247 av_log(s1, AV_LOG_WARNING, "ALSA buffer xrun.\n");
249 err = snd_pcm_prepare(handle);
251 av_log(s1, AV_LOG_ERROR, "cannot recover from underrun (snd_pcm_prepare failed: %s)\n", snd_strerror(err));
255 } else if (err == -ESTRPIPE) {
256 av_log(s1, AV_LOG_ERROR, "-ESTRPIPE... Unsupported!\n");
263 int ff_alsa_extend_reorder_buf(AlsaData *s, int min_size)
265 int size = s->reorder_buf_size;
268 while (size < min_size)
270 r = av_realloc(s->reorder_buf, size * s->frame_size);
272 return AVERROR(ENOMEM);
274 s->reorder_buf_size = size;